1. Field of the Invention
The present invention relates to a solid electrolytic chip capacitor, and particularly to an improvement of the anode terminal and cathode terminal construction of a solid electrolytic chip capacitor.
2. Description of the Related Art
Solid electrolytic chip capacitors generally have the solid electrolytic capacitor construction shown in FIG. 1 employing, for example, tantalum.
Such a solid electrolytic chip capacitor is manufactured as follows: Valve metal wire such as a tantalum wire (constituting anode lead 2) is first implanted into powder of valve metal such as tantalum, and after pressure forming and vacuum sintering to produce a sintered body, a dielectric oxide film is formed on the sintered body. A semiconductor layer and a dielectric layer are next successively formed on this dielectric oxide film to produce capacitor element 1. Cathode terminal 13 is then connected to capacitor element 1, and anode lead 2 is connected to anode terminal 14. Next, capacitor element 1 and anode lead 2, together with each connection portion of cathode terminal 13 and anode terminal 14, are entirely covered by resin sheathing 15. Finally, the exposed portions of cathode terminal 13 and anode terminal 14 are bent into L-shapes along side surfaces 15a, 15b and bottom surfaces 15c, 15d of resin sheathing 15.
However, in solid electrolytic chip capacitors of the prior art such as described in Japanese Utility Model Publication No. 32737/89, projecting surfaces 15e, 15f are provided on the side surfaces of resin sheathing 15 at east above the emergence points of anode terminal 14 and cathode terminal 13 to produce a surface substantially parallel to the outer surface of anode terminal 14 and cathode terminal 13. Alternatively, as described in Japanese Patent Publication No. 30977/91, the outer side surfaces of anode terminal 14 and cathode terminal 13 are provided substantially parallel to the outer side surface of the resin sheathing 15.
In a solid electrolytic chip capacitor according to the above-described prior art, the outer side surfaces tapers to facilitate removal from the die when sheathing with resin, and the form of the anode terminal and cathode terminal therefore conform with this taper during the bending process that follows resin sheathing. As a result, the anode terminal and cathode terminal on the outer side surfaces of a solid electrolytic chip capacitor incline slightly from perpendicular toward the body of the capacitor.
In such an arrangement, the anode terminal and cathode terminal are concealed behind the projecting surfaces above the lead-out points of the anode and cathode terminals, thereby preventing contact of flowed solder with the anode terminal and cathode terminal. As a result, there is a danger of failure of soldering of solid electrolytic chip capacitors to printed-circuit boards, particularly if the printed-circuit boards are mounted on an extremely rapidly moving conveyor during attachment of capacitors to printed-circuit boards by flow soldering.